I'd surely watch for seeds on any flowers with that unusual feature. And if you don't want to grow them, I will! I have plenty of patience which is what it will take. Now so it sets seed - fertilize it with a heavy nitrogen based fertilizer ASAP - this will increase your chance of seed production greatly.

Hopefully all your flowers will look like this:)

You got something interesting there - and definitely worth viewing as being a propagatable subject in both seed and cuttings and/or layering.

Hi, beaker_ch, We did have some odd weather this Spring and maybe my Clematis got nipped by frost...it is still growing out strange..the whole plant is about 5 feet tall and still growing, with dozens of buds.
This is todays photo:

Hi Dax, I think that flower is darling. Not dumb, just doing its own thing. Would sure like one myself...My Polish Clematis is still growing on top getting bigger and adding to the top knot. Sure looks funny. The vine is covered with buds but only the odd one has opened.
Bev

Update on my Polish Clematis...Well the top knot opened into a second flower. From the bottom of the first bloom to the top of the second it is 5" tall! There are a few more blooms open today, but so far they look normal.

That's exactly what I saw happening earlier today. I remember thinking it (the bloom) actually had some "wisteria-like" unfolding happening. It just reminded me of the blooms of a blue wisteria for some reason...

Hi traveller, Are you saying the name of this Clematis is Alba Luxurians ? I got it last year at WalMart (from a box) the name on the box was Polish Spirit. The rest of the vine has around 50 buds, with maybe 20 open. I have to keep it caged in because my daughter has cats that love to lay among the flowers. It really is so beautiful and growing like mad. Each bloom is the size of a large cup.
Bev

Plantzoo
look at this Plantfiles link. http://davesgarden.com/pf/go/63320/
Polish Spirit is a dark purple colour. I wonder if your clematis was mis labelled?
This is my Polish Spirit clematis in the photo.

Hi, I brought this up to show you what my "polish pride"
did last year..now I have found out the real name for it
is "Blue Light". This was the only odd bloom it had, all
the rest were beautiful. Think I'll keep buying the box
plants though, some times you get such nice surprizes.
Now to find a "Polish Spirit" for real.